An altercation inside a Detroit nightclub led to the death of D-12 rapper Proof after an argument allegedly turned into a gunfight, leaving a bouncer wounded, according to sources.

A source that requested anonymity told AllHipHop.com that Proof was in the club after-hours when a heated verbal argument between Proof and a bouncer allegedly broke out and escalated.

Proof was shot and killed around 4:30 am on April 11 and the bouncer was seriously wounded, both with gunshots to the head.

“Proof knocked dude down and stood over him with gun in hand,” a source close to Proof told AllHipHop.com. “Proof shot first. The bouncer on the ground didn’t shoot Proof another bouncer did. Proof was shot 4 times. Twice in the head and twice in the chest/stomach area.”

Police have identified the second man as 35-year-old Keith Bender.

Bender is alive, but is still in critical condition.

“Dude [Bender] is on life support and not expected to live at all,” the source continued.

Investigators are still trying to piece together details of the shooting but have stated they believe two guns were used in the shooting.

According to sources, Proof was licensed to carry his weapon.

Officers have frequently been called to the club, taking 18 incident reports since 1996.

The club was raided in December of 2005 for selling alcohol to minors and Proof’s murder was the third time a shooting had occurred at or near the club.

“All this s**t is senseless and real f**ed up. Proof was a longtime friend who wouldn’t stay the f**k out the hood. To many jealous people in the hood mad cause you made it.

“8 Mile [road] near Hayes on Detroit’s Eastside at 4 am in the morning? That Triple C spot always has drama up there. Why was he there?” the source continued.

The police questioned one witness in the case and seek to speak to others to find suspects.

The club did not have a video surveillance system police, officers revealed.

Proof served as Eminem’s best man in the rapper’s short-lived wedding to Kim Mathers.

The rapper, whose real name is DeShaun Holton, leaves behind five children.